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A new optoelectronic oscillator (OEO) is implemented for a novel self-sustained flat-topped self-oscillating optical frequency comb generator (SO-OFCG), which can be deployed in terahertz optical transmission. The OFCG is designed from a cascaded configuration of an electro-absorption modulator and a polarization controller. In this work, the radio frequency source of a traditional-OFC scheme is replaced by the OEO. The frequency spacing of the generated spectrum is defined by the OEO∼20 GHz that contains 15-healthy frequency tones. The carriers are modulated using the 16-quadrature amplitude modulation technique and transmitted across an SSMF implemented in a loop to complete a fiber span of 80 km-240 km. Overall, 1.12Tbps transmission can be achieved with the help of the given setup. At the receiver side, a homodyne coherent receiver is designed using the proposed OFCG to receive the signal. The conventional local oscillator lasers are replaced by the SO-OFCG generated from the received central optical carrier. Through offline DSP, the received optical signals are remunerated from various signal distortions and nonlinear impairments by utilizing digital backpropagation, constant modulus algorithm, and blind phase search algorithm at the receiving end. The system is analyzed regarding the bit error rate, symbol error rate, Q-factor, and error vector magnitude.

Polarimetry has been demonstrated essential in various disciplines, such as optical communications, imaging, and astronomy. On-chip nanostructures for polarization measurements are most expected to replace the conventional bulk elements, and hence minimize the polarimeter for integrated applications. Some on-chip nanophotonic polarimeter via polarization detection has been implemented, in which the separation of two spin polarized states is needed. However, due to the relatively low coupling efficiency or complicated photonic silicon circuits, on-chip polarimetry using a single device still remains challenging. Here, we introduce and investigate an on-chip polarimeter with nanostructures using the inverse design method. The developed device shows the ability to detect the four polarization components of light, two of which are the spin polarizations, and the other two are the linear polarizations. The retrieved Stokes parameters with experimentally tested data are in close agreement with the numerical results. We also show the proof of concept demonstration for high-speed Stokes vector optical signals detection. In the high-speed communication experiment with data rate up to 16 GBd, the detected optical signals via polarization measurements at multiple wavelengths in the C-band were recovered with the bit error rate below the 20% forward error correction threshold. The proposed on-chip polarimeter shows promising performance both in Stokes polarimetry and high-speed optical communication applications.

During the utilization, blending, transportation, and storage, a significant amount of volatile organic compounds (VOCs) are released from inks, posing risks to both human health and the ecological environment. This study sought to identify the types and structures of VOCs released from four types of solvent-based inks (referred to as CAB, PVB, AKR, and Rs inks) in high-temperature settings and to assess the bioaccumulation factors, developmental toxicity, and acute toxicity of these released VOCs. The findings revealed that all tested inks released substantial amounts of VOCs in high-temperature environments. CAB and PVB inks released fewer types of VOCs with relatively smaller molecular weights, primarily with carboxylic acid groups and hydroxyl groups, while AKR and Rs inks released more types of VOCs with larger molecular weights, including polycyclic aromatic hydrocarbons. Toxicity analysis indicated that although the primary VOCs released from CAB and PVB ink displayed some developmental toxicity, their bioaccumulation factors were below 100. The principal VOCs from AKR ink did not exhibit developmental toxicity. Conversely, the predominant VOCs from Rs ink not only demonstrated developmental toxicity but also had bioaccumulation factors exceeding 100. Additionally, the VOCs released from CAB, PVB, and AKR inks exhibited stronger acute toxicity to luminescent bacteria, while those from Rs ink showed greater acute toxicity to fish. These results offer a scientific foundation for the safe usage of inks and environmental conservation. Implications: This study provides critical insights into the types and toxicity of volatile organic compounds (VOCs) emitted from solvent-based inks under high-temperature conditions. The findings have significant implications for environmental policy and industrial practices. The identification of VOCs, particularly from CAB, PVB, AKR, and Rs inks, and their associated health and ecological risks, can inform regulatory bodies about the need for stricter emission controls. The assessment of bioaccumulation factors and acute toxicity highlights the potential for these compounds to accumulate in organisms and impact aquatic life, necessitating the development of safer ink formulations and disposal methods. Policymakers can leverage these results to update environmental regulations, promote the use of eco-friendly inks, and encourage technological advancements in the printing industry to minimize VOC emissions. Additionally, the study underscores the importance of continued research in this area to further understand the long-term effects of VOCs on human health and the environment, ultimately guiding more sustainable and responsible industrial practices [ABSTRACT FROM AUTHOR]

A novel two‐parameter sensor is proposed based on the abrupt taper and micro‐arc Michelson interferometer (MI) in single‐mode fiber. When there is a regular change in the liquid level or temperature, the phase difference changes, and the spectral intensity or wavelength of the interfering valleys of this sensor is directionally shifted. This study enriches the construction of MI and provides a new perspective on liquid level measurement. We experimentally explored the sensor's sensing performance over temperature and liquid level: this sensor's temperature sensitivity and liquid level sensitivity were up to 62.9 pm/°C and 0.2896 dB/mm, respectively. In addition, this sensor is characterized by compactness, simplicity, low cost, and high reliability, and it is suitable for measurement of liquid level and temperature, expanding the application field of MI. [ABSTRACT FROM AUTHOR]

Based on the synergistic modulation of electromagnetic parameters and microstructure design, multidimensional porous magnetic carbon-based nanocomposites have become ideal materials with efficient absorption properties. What's more, a carbon-magnetic alloy composite is a commonly used and efficient microwave absorber. In this paper, Co7Fe3/Co@CBC (CFCC) nanocomposites with strong magnetism, a three-phase composition, and a three-dimensional porous structure were synthesized by reducing Fe2+ and Co2+ using chestnut-shell biomass carbon (CBC). Biomass carbon with a higher specific surface area provides numerous active sites for Co7Fe3 nanosheets and Co nanospheres to form three-dimensional ping-pong chrysanthemum-like nanocomposites, which generate rich heterogeneous interfaces and conductive network structures. By adjusting the amount of added biomass, the electromagnetic parameters can be effectively regulated to achieve efficient microwave absorption properties. When the amount of biomass added varies within the range of 1.0 to 2.5 g, all samples exhibit a favorable effective absorption bandwidth (EAB) of over 5.88 GHz. In particular, the CFCC-2.0 composite exhibits optimal microwave absorption properties, with a minimum reflection loss (RLmin) value of −59.25 dB and an EAB of 6.34 GHz at a thickness of 2.8 mm. The simulation and modeling analysis results of radar cross section (RCS) further confirm the exceptional attenuation capability of composite materials at multiple incident angles. The exceptional microwave absorption properties and stability of EAB for the Co7Fe3/Co@CBC nanocomposite make it a promising candidate in the field of absorbing materials. This work also provides some feasible ideas for designing stable broadband wave-absorbing materials. [ABSTRACT FROM AUTHOR]

A new type of Michelson interferometer (MI) based on a double hook structure is proposed for measurement of liquid level and temperature. The optical fiber MI based on the double‐hook structure is fabricated using a hydroxide flame heating device. Furthermore, the angle and sensing length of the double‐hook structure can be controlled by a rotating platform. The sensor is fixed on a ruler, which is set vertically on the iron support stand employing a beaker clamp, and the position of the beaker clamp is adjusted so that the double hook structure of the sensor overflows the water surface in the beaker. The temperature and liquid level sensitivities of the sensor are 129.8 pm/°C and −186.2 pm/mm, respectively. The novel optical fiber MI based on the double‐hook structure has the advantages of high sensitivity, low cost and easy fabrication, which has a great market prospect in production and life. [ABSTRACT FROM AUTHOR]